NCERT Class 11-Biology: Chapter –7 Structural Organization in Animals Part 3

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Question 9:

Give two identifying features of an adult male frog.

Answer:

The two identifying features of an adult male frogs are:

(i) Presence of vocal sacs: The male frogs have saggy skinned vocal sacs in their necks which amplify their sounds for attracting female frogs for mating.

(ii) Presence of Copulation pad: The male frogs have a copulatory pad on the forelimbs which helps in holding the female tightly during mating.

Question 10:

Which mouth part of cockroach is comparable to our tongue?

Answer:

Hypopharynx is the mouth part of cockroach which is comparable to our tongue because the hypopharynx is located medially and it is a flexible lobe which is comparable to a human tongue.

Question 11:

The digestive system of frog is made of the following parts. Arrange them in an order beginning from mouth.

Mouth, oesophagus, buccal cavity, stomach, intestine, cloaca, rectum, cloacal aperture

Answer:

The correct arrangement of the given parts beginning from mouth is:

Mouth

Buccal cavity

Oesophagus

Stomach

Intestine

Rectum

Cloaca

Cloaca aperture

Question 12:

What is the difference between cutaneous and pulmonary respiration?

Answer:

  • Cutaneous respiration refers to the exchange of gases which occurs through the from the skin while pulmonary respiration refers to the exchange of gases through the lungs.

  • Cutaneous respiration is generally considered as a secondary mode of respiration while pulmonary respiration is considered to be the sole mode of respiration. Some organisms like frogs have the ability to breathe through the skin and also have lungs.

  • Cutaneous respiration can be observed mainly in insects and amphibians while pulmonary respiration can be observed in mammals.

Question 13:

Special Venous connection between liver and intestine and between kidney and intestine is found in frog, what are they called?

Answer:

Special venous connection between the liver and intestine is known as the hepatic portal system and between kidney and intestine is known as the renal portal system. These portal systems are very essential. The blood obtained from portal veins are from these portal systems.

Short Answer Type Questions

Question 1:

Give the location of hepatic caeca in a Cockroach. What is their function?

Answer:

The hepatic caeca which are also known as gastric caeca is a 6-8 narrow and hollow ring-like blind tubules which are present in the junction of the foregut and midgut. Since cockroaches are omnivorous organisms the hepatic caeca secrete the digestive enzymes for the facilitation of digestion in cockroaches. Thus, they help in the digestion of food in cockroaches.

Question 2:

Frogs are beneficial for mankind, justify the statement.

Answer:

Frogs are very beneficial for mankind because:

  • They are an important part of the food chain. They are very important predators of insects and prey of snakes, vultures, etc.

  • They help the farmers by eating insects and pests for their diet and protecting the crops from insect infection.

  • They are also used as a food source for humans in some regions of the world.

  • They are widely used by researchers for various experimentation and testing and they are also useful in environmental indicators.

Question 3:

The body of sponges does not possess tissue level of organisation though it is made of thousands of cells. Comment.

Answer:

Most of the multicellular organisms possess specialized or advanced tissue level but sponges have a cellular tissue level. Their tissue organization is simple and each cell functions independently. They are loose cell aggregates although some specialized functions are carried out with division of labour among the cells. They do not form tissues and their bodies perforated which allows water to pass through them easily.

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